This invention relates to a device to meter the flow of gaseous fuel to an internal combustion engine. In most internal combustion engines, either a carburetor or an electronic fuel injection system is used to supply fuel to the engine cylinders. Both types of devices fail to supply fuel and air in mixtures which are always completely combusted in the engine cylinders. This failure results in the waste of precious fuel and the exhaust of noxious pollutants. Further, emission control systems are required to deal with the pollutants from incompletely combusted fuel thereby adding to the cost of, and increasing the complexity of, the engine.
My invention supplies fuel in a gaseous form and in correctly metered amounts to each individual cylinder of an internal combustion engine, and at the same time provides a precise amount of air to each cylinder. The gaseous fuel delivered in correctly metered amounts and mixed with air according to the engine load demand burns more completely. This provides better fuel economy and at the same time reduces pollution and the need for expensive and complex pollution control devices. By the use of my invention with an internal combustion engine, it is possible to eliminate a fuel pump, carburetor, and emission control system, thereby reducing the complexity and cost of the engine. In addition, the devices which incorporate my invention are of sturdy construction, have few moving parts, and are easily maintained.
The vapor or combination vapor/air control device embodying my invention operates to meter fuel in gaseous forms such as LP gas, hydrogen, gasoline in a gaseous state, etc. The fuel is supplied by either a pressurized fuel tank as in the case of LP or hydrogen gas, or by a system which converts liquid gasoline into a gaseous state. Such conversion systems are well-known in the art and not a part of my invention.
The fuel is supplied under a positive pressure to a reservoir chamber in the vapor control section of the device. The gaseous fuel in the reservoir chamber is metered out to the individual engine cylinders by first passing through valves to individual chambers equal in number to the number of engine cylinders. The fuel exits from the individual chambers either directly by a suction caused by the intake stroke of each cylinder or indirectly by the opening of a demand valve associated with each chamber which also operates by the suction caused by the intake stroke of the cylinder. By a proper correlation of the valves between the reservoir and individual chambers with the throttle, a precise amount of fuel is metered to the individual chambers. This fuel is then released on demand to the cylinder associated with each individual chamber.
In addition to metering the correct amount of fuel to a cylinder, the cylinders must also be supplied with the proper amount of air in order to completely combust the fuel. In order to supply the necessary amount of air, a vapor control device is associated either with an existing carburetor in an internal combustion engine or with an air control unit. If a carburetor is used, it does not perform the function normally associated with it of mixing air and fuel. The function of either the carburetor or the air control unit is to meter or provide air to the intake port of a cylinder. The proper amount of air is supplied to each cylinder on its intake stroke by control via connections to the throttle of the engine and an air flap in the carburetor or air control unit and to a one-way air valve associated with each individual cylinder. The one-way air valve opens on the intake stroke of the cylinder to meter the necessary amount of air to be mixed in the intake port of the cylinder with the fuel delivered by the vapor control unit.